A location on bovine chromosome 20 has been found to be involved in the origins of three of the most prevalent and costly bacterial diseases that affect feedlot cattle—pinkeye, foot rot and bovine respiratory disease (pneumonia), according to new ARS research. Click the image for more information about
it.

ARS is USDA's chief intramural scientific research agency, and this research supports USDA's priority of promoting international food security.

Bovine respiratory disease accounts for 75 percent of feedlot illnesses and up to 70 percent of all deaths, with economic losses to cattle producers exceeding $1 billion annually. The estimated costs for pinkeye are $150 million yearly, and losses to dairy producers due to foot rot range from $120 to $350 per animal.

Casas and his colleagues combined pinkeye, foot rot and bovine respiratory disease to represent overall pathogenic disease incidence. They developed half-sibling families from crossbreed bulls: a Brahman-Hereford, a Brahman-Angus, a Piedmontese-Angus and a Belgian Blue-MARC III (part Red Poll, Pinzgauer, Hereford and Angus). An analysis of DNA samples from the 240 offspring infected with one or more of the diseases revealed a genetic marker, called a quantitative trait locus (QTL), on chromosome 20. This QTL is associated with the three diseases.

Chromosome 20 is located near genetic markers related to other diseases and may have a significant effect on the overall health of cattle, according to Casas. Identifying genetic markers responsible for disease would provide an opportunity to produce cattle with increased disease tolerance, which also could help reduce economic loss associated with diseases.